The present invention relates to a fastener for fastening an end portion of a wood beam to a generally upright surface of a beam-anchoring member, such as a wood post or other beam. More particularly, the invention relates to such a fastener which compresses the end portion of the beam against the upright surface of the beam-anchoring member to provide a long-lasting tight junction despite subsequent shrinkage of the wood.
In the use of large wood beams, such as laminated beams, box beams or dimension lumber beams for spanning relatively long distances, it has become increasingly critical to provide end connections with posts or other beam-anchoring members which not only provide support vertically and laterally, as do conventional beam and joist hangers, but which also compress the ends of the beam longitudinally to provide a lasting tight joint. Otherwise, a gradual separation occurs between the ends of the beam and the beam-anchoring members due to wood shrinkage, which weakens the joint structurally.
One way of diminishing this problem in the past has been to use spring and washer systems on the connecting hardware to compensate for wood shrinkage. However, such systems require considerable labor to install and are limited in their ability to compensate for excessive shrinkage. Other systems, such as those shown in U.S. Pat. Nos. 5,061,111, 5,242,239 and 5,253,945, provide mechanisms for compressing the end portion of the beam against the beam-anchoring member to compensate for expected shrinkage. However, these latter systems likewise require considerable installation labor, due to the need first to connect the beam to the beam-anchoring member and then to compress the end portion of the beam as separate steps. Moreover, such end-compression systems do not adequately compensate also for future shrinkage of a wood beam-anchoring member, which can also permit gradual separation of the joined members, and do not adequately provide for side fastening of the beam to resist lateral forces and transverse splitting of the end portions.